get image height and width in file tag using javascript [duplicate]

Answer 1

This is impossible to do in a cross-browser way.

The only cross-browser way that comes to my mind (but is not simple) is to upload the file ajax style, render that image (could be hidden) and get its size with img.width and img.height.

Hope this helps. Cheers

Answer 2

Use the onload event:

document.getElementById('testimg').onload = function() {
  alert(document.getElementById('testimg').offsetHeight);
}

You can change the action in the function, for example, making your buttons visible, or un-disabled, up to you.

Not sure I understand your question, but Javascript will need to load the image before you can get its dimensions.